The World Resources Institute (WRI) has updated and expanded its analysis of six mandatory cap-and-trade proposals for carbon emissions. WRI's analysis was updated to include recent proposals from Sens. Joseph Lieberman, I-Conn., and John Warner, R-Va., as well as Sens. Jeff Bingaman, D-N.M., and Arlen Specter, R-Pa.

WRI says the analysis will be a valuable tool in evaluating the environmental stringency of proposed legislation. A new chart in the updated analysis compares the cumulative emissions budget outlined in each bill now being considered by Congress.

"Charting a course for mandatory emissions reductions is critical, but targets alone do not allow for a thorough comparison of the different bills," says Jonathan Pershing, director of WRI's Climate and Energy Program. "This analysis highlights the fact that a cap-and-trade program alone will not solve the global warming challenge. Complementary policies will be needed."

WRI adds that the analysis does not depict the economic costs or impacts resulting from these policies. For more information on the updated analysis, visit wri.org/usclimatetargets.